I. Field
The present disclosure relates generally to communication, and more specifically to techniques for transferring capabilities between a user equipment (UE) and a wireless communication network.
II. Background
A UE (e.g., a cellular phone) may communicate with a wireless communication network in order to obtain various communication services such as voice, video, packet data, messaging, broadcast, etc. The UE may register with the network prior to obtaining any services. During registration, the UE may provide a list of its capabilities to the network, and the network may likewise provide a list of its capabilities to the UE. The UE and the network may also exchange capability lists when the UE accesses the network before or after registration, e.g., when the UE accesses a new base station. Each capability list may allow the recipient entity (the UE or network) to know which capabilities the sending entity supports and thus which capabilities and features may be invoked and used for various services.
The network may broadcast some or all of its capabilities. This may then allow the UE as well as other UEs to receive the network capabilities without having to exchange signaling with the network. The network may also send its capabilities in a point-to-point manner to the UE. In this case, the UE should be registered (or in the act of registering) with the network and may explicitly interact with the network to obtain the network capabilities.
The UE may send its capabilities to the network in a point-to-point manner before, during or following registration. The UE may also send its capabilities in other instances, such as when entering an active state with the network in order to invoke a service in the network (e.g., make an outgoing call), to respond to a paging request from the network for some service invoked by the network (e.g., receive an incoming call), etc.
The UE may send its capabilities in an information element (IE) to the network. The network may likewise send its capabilities in the same or different information element to the UE. An information element may be a parameter that may be included in a message and may be defined with specific fields of specific lengths. Different capabilities may be conveyed via different fields of the information element.
The UE and the network may transfer capability information using specific messages and information elements capable of conveying capabilities known at the time the messages and information elements are defined. However, new capabilities may be added as wireless technology evolves, as UE design improves, etc. The ability to include information on new capabilities using existing messages and information elements may be restricted, e.g., because the existing messages and information elements cannot be expanded to include new capability information. New messages and/or new information elements may be defined for conveying new capability information. However, these new messages and/or information elements may cause compatibility issues for UEs and networks that do not support these new messages and/or information elements. In addition, these new messages and/or information elements may have development impacts on network entities transporting them.
There is therefore a need in the art for techniques to transfer new capability information in a backward compatible manner and/or with little or no development impact.